--I'd have to see the 15 mpg and better if the truck you're talking about is the one in your profile... Are you going across the flat desert at 55 mph with a backwind? Worst towing at 13.5 with a 5.4? You have a factory anomaly if that's the case. Don't ever sell it.

the truck in my profile is the one im talking about. and thats driving in a hilly area of tennessee, not a desert. part of it could be how i drive it, very seldom run it above 2500 rpm when driving, usuallyshift at around 2000. never had it above 3500 rpm towing. if the speed limit is 70, and i hit a hill with a big load i dont try to maintain 70. if i have to slow down to 60 or 65 so be it. part of it could be a factory anomaly. me and my cousin both bought factory stock mustang lx 5.0 a long time ago. his had about 20 more rwhp than mine did and would beat it by about a second in the 1/4 mile. both cars identical down the the rear end. he kept his, i sold mine.

--Either that or you're using some seriously fuzzy math. Your getting the mpg of a diesel when you're towing. Highly unlikely.

every time i fill her up, i fill her to the top. and ive checked my mileage on every tank since ive had her. last weekend i filled her up, drove to asheville and back, 285 miles, put 18.3 gallons of gas in her when i got back. 285/18.3=15.57 mpg if my math is the same as yours. during race season the trailer is never unhooked from her and i average between 13.5-13.8 mpg.

--5.4 4x4 regular cab 6700 miles on the odo 15.3 on the last full tank. the last tank was around town with no extended expressway travel. during the holiday season we pulled a parade float a little over 2800 miles and the truck averaged 11.2. the interesting part was that the mpg changed very little during the mountain driving which included the mtns of western nc and sw virginia area.

i get the same around town i do on the interstate, so i would think yours would be about the same too. and glad to see your math is as fuzzy as mine is. i get a little more than you towing though.

 

If it's true, I'm jealous. I don't think I could keep the RPMS that low no matter what anyhow. I'm not surprised with the Mustangs. I've heard of things like that all the time.